语法另一道疑惑

寂寞的自由

12. ??? Affording strategic proximity to the Strait of Gibraltar, Morocco was also of interest to the French throughout the first half of the twentieth century because they assumed that if they did not hold it, their grip on Algeria was always insecure.  B(A) if they did not hold it, their grip in Algeria was always insecure
(B) without it their grip on Algeria would never be secure
(C) their grip on Algeria was not ever secure if they did not hold it
(D) without that, they could never be secure about their grip on Algeria
(E) never would their grip on Algeria be secure if they did not hold it

疑问点：D中的without that 新东方说that 必须指代复数可数名词，有这个GMAT语法定理吗？！
另外，A中的IF是不是不能同原句题干中的THAT连接词直接连接在一起呢？不能同时用两个连接词呢？谢谢大家
正确答案是B

cherry3213

关于D中的疑点, 新东方说"that"用来指代重复的单数名词, 它不可能指代复数名词的. 因为这里需要一个人称指代,所以要用it

dreadpower

请规范格式，好吗？？

   请参见这个http://forum.chasedream.com/dispbbs.asp?boardID=23&ID=32446

   谢谢配合